1 files changed, 147 insertions, 0 deletions
diff --git a/drivers/serial/serial_semihosting.c b/drivers/serial/serial_semihosting.c
new file mode 100644
index 00000000000..7c7c5d94558
--- /dev/null
+++ b/drivers/serial/serial_semihosting.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2022 Sean Anderson <sean.anderson@seco.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <serial.h>
+#include <semihosting.h>
+
+/**
+ * struct smh_serial_priv - Semihosting serial private data
+ * @infd: stdin file descriptor (or error)
+ */
+struct smh_serial_priv {
+	int infd;
+	int outfd;
+};
+
+#if CONFIG_IS_ENABLED(DM_SERIAL)
+static int smh_serial_getc(struct udevice *dev)
+{
+	char ch = 0;
+	struct smh_serial_priv *priv = dev_get_priv(dev);
+
+	if (priv->infd < 0)
+		return smh_getc();
+
+	smh_read(priv->infd, &ch, sizeof(ch));
+	return ch;
+}
+
+static int smh_serial_putc(struct udevice *dev, const char ch)
+{
+	smh_putc(ch);
+	return 0;
+}
+
+static const struct dm_serial_ops smh_serial_ops = {
+	.putc = smh_serial_putc,
+	.getc = smh_serial_getc,
+};
+
+static int smh_serial_probe(struct udevice *dev)
+{
+	struct smh_serial_priv *priv = dev_get_priv(dev);
+
+	priv->infd = smh_open(":tt", MODE_READ);
+	return 0;
+}
+
+U_BOOT_DRIVER(smh_serial) = {
+	.name	= "serial_semihosting",
+	.id	= UCLASS_SERIAL,
+	.probe	= smh_serial_probe,
+	.priv_auto = sizeof(struct smh_serial_priv),
+	.ops	= &smh_serial_ops,
+	.flags	= DM_FLAG_PRE_RELOC,
+};
+
+U_BOOT_DRVINFO(smh_serial) = {
+	.name = "serial_semihosting",
+};
+#else /* DM_SERIAL */
+static int infd = -ENODEV;
+static int outfd = -ENODEV;
+
+static int smh_serial_start(void)
+{
+	infd = smh_open(":tt", MODE_READ);
+	outfd = smh_open(":tt", MODE_WRITE);
+	return 0;
+}
+
+static int smh_serial_stop(void)
+{
+	if (outfd >= 0)
+		smh_close(outfd);
+	return 0;
+}
+
+static void smh_serial_setbrg(void)
+{
+}
+
+static int smh_serial_getc(void)
+{
+	char ch = 0;
+
+	if (infd < 0)
+		return smh_getc();
+
+	smh_read(infd, &ch, sizeof(ch));
+	return ch;
+}
+
+static int smh_serial_tstc(void)
+{
+	return 1;
+}
+
+static void smh_serial_puts(const char *s)
+{
+	ulong unused;
+
+	if (outfd < 0)
+		smh_puts(s);
+	else
+		smh_write(outfd, s, strlen(s), &unused);
+}
+
+struct serial_device serial_smh_device = {
+	.name	= "serial_smh",
+	.start	= smh_serial_start,
+	.stop	= smh_serial_stop,
+	.setbrg	= smh_serial_setbrg,
+	.getc	= smh_serial_getc,
+	.tstc	= smh_serial_tstc,
+	.putc	= smh_putc,
+	.puts	= smh_serial_puts,
+};
+
+void smh_serial_initialize(void)
+{
+	serial_register(&serial_smh_device);
+}
+
+__weak struct serial_device *default_serial_console(void)
+{
+	return &serial_smh_device;
+}
+#endif
+
+#ifdef CONFIG_DEBUG_UART_SEMIHOSTING
+#include <debug_uart.h>
+
+static inline void _debug_uart_init(void)
+{
+}
+
+static inline void _debug_uart_putc(int c)
+{
+	smh_putc(c);
+}
+
+DEBUG_UART_FUNCS
+#endif